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RFI 10.03.2020 - Appendix C - Memorandum cooroibah waterway crossing · MCU16/0099.01
Aurecon Australasia Pty Ltd T +61 7 3173 8000
ABN 54 005 139 873 F +61 7 3173 8001
Ground Floor, 25 King Street E [email protected]
Bowen Hills QLD 4006 W aurecongroup.com
Locked Bag 331
Brisbane QLD 4001
Australia
Memorandum
To Adam Pfitzner From Con Sweeney
Matthew Dunworth, Mitti Goon,
Copy Reference 247473-CROIBH
Tom Montgomery
Pages
Date 2020-02-19 (including this page)
8 + Appendices
Subject Cooroibah waterway crossing – access construction trafficability
A site investigation of the waterway crossing located on Lot 46 at 23 Jirrima Crescent in Cooroibah
included geotechnical testing at the concrete crossings edges, and assessment of the trafficability of
the concrete crossing. Discussions with the land owner about the crossing construction as well as
visual inspection notes have been detailed.
1 History of water crossing
The following information on the history of the waterway crossing was obtained from the land owner’s
recollection 20-25 years ago, when the crossing was first constructed:
◼ Initially around $900 worth of rock was dumped into the waterway to form a crossing. All rock
eventually sunk into the waterway.
◼ The land owner was a concrete truck driver who would intermittently place leftover concrete over
the waterway. Over time, the concrete gradually formed the existing crossing.
◼ The concrete strength may vary between 20MPa to 40MPa.
◼ It has been confirmed that there is no steel reinforcement in the concrete crossing.
◼ The concrete thickness varies between 200 - 400mm and potentially 450mm in the middle of the
crossing. The concrete thins out towards the vehicle access edges on the eastern and western
sides.
◼ Concrete lines the dam edge 1-2 m into the water on the southern side of the crossing (opposite to
the property fence).
◼ It has been advised that RFSQ (Rural Fire Service Queensland) have previously used the crossing
to access properties on the western side of the crossing in emergencies.
2 Visual inspection of concrete crossing
The following observations were made upon visual inspection of the extent of the concrete crossing:
◼ Crossing dimensions: 26m (East to West) x 13.5m (North to South). The crossing dimensions are
marked on the image of the crossing in Figure 1.
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Fence line
26 m East to West
Approximately 13.5 m North
to South
Figure 1: Borehole location plan
◼ The concrete has been gradually added to the crossing during its construction and varies in surface
condition, aggregate size and type of concrete. The main access path of the crossing surface is
undulating (due to the different layers/additions of concrete) with differences in height of 100mm-
150mm in some places. Figure 2 is an image of the surface of the access path and the condition of
the concrete surface is shown in Figure 3.
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Figure 2: Surface of concrete crossing (east to west)
Figure 3: Condition of concrete surface
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There is little to no indication that formwork was used with no straight or flat edges. The concrete
finishes appear to be spread by hand, with no assurance that correct compaction techniques were
applied.
◼ The concrete extends up to the fence line for most of the length of the crossing.
◼ The concrete along the fence line is overlain with topsoil and grass cover that has formed over time
from flooding. A DCP test undertaken in this location found that the DCP refused at 0.15-0.20m bgl
(below ground level). Figure 4 is an image of the crossing along the fence line.
◼ The concrete is built up along the dam edge on the southern side with an approximate 200-500mm
difference between the rest of the crossing. Figure 5 presents a view of the concrete built up along
the dam edge on the southern side of crossing.
◼ Approximately 0.5m difference in the level between the two dams/waterways on each side of the
crossing.
◼ No major cracking and very minimal crumbling was observed in the concrete.
Figure 4: View of crossing along the fence line
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Figure 5: Built up concrete edge of dam on southern side of the crossing
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3 Geotechnical investigation
A geotechnical site investigation was undertaken at specific locations within the investigation area to
collect geotechnical information pertaining to the subsurface conditions of the waterway crossing.
The site investigation comprised:
◼ Three (3) boreholes to a maximum depth of 3.0 m
◼ In-situ testing
Soil descriptions have been determined by an experienced engineer in the field through tactile
assessment and in situ testing.
All aspects of the site investigation were carried out in accordance with AS1728-2017 “Geotechnical
site investigations”. The site work was undertaken according to the Aurecon Health and Safety Plan
and Environmental Management Plan developed for the project. In adherence to these plans, Aurecon
undertook Dial Before You Dig (DBYD) searches for services in the local area. A third-party contractor
cleared each borehole location for the presence of buried services before commencing soil augering.
All test locations were recorded using a hand-held GPS (+/- 5m accuracy) to the UTM GDA94 format.
Ground elevation data was retrieved from the State of Queensland’s Department of Natural
Resources, Mines and Energy online mapping tool “Queensland Globe”.
3.1 Boreholes
A total of three (3) boreholes were augered on the site using a hand auger. Two (2) boreholes were
augered on the western side of the crossing, and one (1) was augered on the eastern side (Figure 5).
The boreholes were backfilled with soil cuttings and compacted upon completion. Bore logs are
presented in Appendix A.
3.2 In-situ testing
DCP testing was undertaken at each borehole location to a maximum depth of 3.0m bgl to assess the
in-situ strength of the subsurface soil profile. DCP testing was undertaken in accordance with AS
1289.6.3.2-1997. The DCP test results obtained at each borehole location are presented in the logs
provided in Appendix A.
3.3 Subsurface profile
The site subsurface profile comprised of topsoil underlain by typically stiff clay soil that increases in
consistency with depth. In BH2 the soil was saturated at 1.9m bgl, and the water would recharge as
the remainder of the hole was being completed. Borehole locations are presented in Figure 5. A
summary of the strata encountered within the boreholes is presented in Table 1.
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Table 1: Borehole strata summary
Location Stratum Material Depth (m) bgl Consistency/Strength
Layer
From To
BH1 TOPSOIL Silty CLAY (CH) 0 0.32 Firm
ALLUVIUM Sandy CLAY (CI - CH) 0.32 1.20 Stiff to Very Stiff
(REF)
BH2 TOPSOIL Sandy CLAY (CL) 0 0.40 Very Stiff
ALLUVIUM Silty Sandy CLAY (CI) 0.40 0.70 Stiff - Soft to Firm
Silty CLAY (CI-CH) 0.70 0.90 Soft to Firm
Sandy CLAY (CI-CH) 0.90 1.40 Very Stiff
Silty CLAY (CH-CI) 1.40 2.75 Hard
Sandy CLAY (CH) 2.75 2.90 Hard
Clayey SAND 2.90 3.0 (TD) -
BH3 TOPSOIL Silty CLAY (CI-CH) 0 0.40 Very Stiff
ALLUVIUM Silty Sandy CLAY (CI) 0.40 0.80 Stiff
Silty CLAY (CH) 0.80 1.37 Very Stiff - Stiff
(REF)
Note: 1. TD = Target Depth 2. REF = Refusal 3. CL = Low plasticity CLAY; CI = Medium plasticity CLAY; CH = High plasticity
CLAY
4 Access construction trafficability
Aurecon understands that the following vehicles are required to access the site via the concrete
crossing:
◼ Standard 4WD vehicles (up to approx. 5 at any one time).
◼ Tipper Truck with trailer (carrying excavator)
◼ Tipper truck - approx. 8 tonnes
◼ Excavator - approx. 8 tonnes
◼ Concrete trucks (5 to 6) in and out of the site - standard size
◼ Truck for fencing contractor - approx. 4 tonnes
◼ 3x semi-trucks to deliver pole/tower - size between 13m and 18m long trailers.
◼ A typical 100 tonne wheeled or tracked crane to lift the structure into place
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4.1 Trafficability
As observed during the site investigation, the trafficability of the concrete crossing, including the areas
where there is no concrete, is suitable for standard 4WD vehicles to traverse the crossing. From the
landowner’s experience, the crossing has also supported the movement of standard sized concrete
trucks. The results from the geotechnical investigation indicate that the layer of concrete is surrounded
by typically stiff clay that increases in consistency with depth, therefore larger vehicles (i.e. trucks,
cranes) should be sufficiently supported to safely traverse the crossing in order to access the site.
4.2 Manoeuvrability
Potential manoeuvrability issues of semi-trucks of lengths between 13m and 18m in length with 5-6m
clearance in width between adjacent trees within the crossing, limiting turning on the crossing. Vertical
clearance of trees appears to be satisfactory however caution with a few small overarching branches
is recommended.
4.3 Access
There concrete crossing is located at the bottom of the gully in a natural watercourse and below a dam
wall’s overflow outlet. As the structure is an obstruction within a natural watercourse and there are no
underground pipes to allow the water to travel under the crossing, it is expected that access to the site
will be restricted during the wetter parts of the year. Future plans for construction or access for
maintenance should take this into account.
5 Conclusions and Recommendations
The existing waterway has been filled with rock and concrete, and the concrete crossing is currently in
good condition with no major cracking and very minimal crumbling. The sight of the crossing has been
observed as clean and neat. From the results of the geotechnical investigation, the soil surrounding
the crossing structure is typically stiff clay that increases in consistency with depth. The history of the
crossing and findings from the site investigation conclude that the existing crossing in its current
condition is trafficable and suitable for 4WD vehicles and larger vehicles (i.e. trucks, cranes) to
traverse in order to access the site.
As discussed in Section 4.3, the crossing structure blocks a natural waterway channel and there are
no means for the water to flow through under the crossing. Therefore, it is recommended for vehicles
to avoid traversing the crossing when the water is high, particularly during wet periods of the year.
Should you require additional information or clarifications please don't hesitate to contact me
Kind Regards
Con Sweeney
Senior Civil Engineer, Civil Infrastructure
RPEQ 14331
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Appendix A
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25 King St
Bowen Hills QLD 4006
ph: +61 7 3173 8000
e: [email protected]
SOIL BH1
Client: NBN Driller: N/A Commenced:30/01/2020
Project: Cooroibah Waterway Crossing Rig: Hand Auger Completed: 30/01/2020
Location: Cooroibah Easting: 499967 m
Project Number: 247473 Northing: 7085465 m
Elevation: 10 mAHD Sheet:1 of 1
Drilling Soil Description Testing Strata
Information Information
Elevation (mAHD)
Moisture Content
MATERIAL DESCRIPTION Comments /
Consistency / DCP Values
Sample Type
Groundwater
Graphic Log
Soil Type, Colour, Plasticity or Particle Test Results /
Depth (m)
Relative Density (Blows/100mm Penetration)
Depth (m)
Characteristic, Secondary and Minor Components Origin
Method
VS S F St VSt H
VL L MD D VD C
2 6 10 14 18
USC
1 2 3 4 5 2 4 6 8 1 0 1 2 1 4 1 6 1 8
0 m: TOPSOIL: Silty CLAY CH >PL TOPSOIL
D
Dark brown, high plasticity, with minor fine grained sand,
organics (rootlets), >PL, stiff
D 0.15 m: increase in sand content
0.32 m: Sandy CLAY CI ALLUVIAL
D Brown grey mottled orange, medium plasticity, with fine
0.5 grained sand, >PL, stiff 9.5 0.5
HA
0.6 m: Sandy CLAY CH ~PL
D Grey mottled / indurated red, low to medium plasticity,
fine to medium grained sand, ~PL, very stiff
1.0 9.0 1.0
D 1.16 m: becomes pale grey stained red, with fine to
medium subangular gravel
BH1 Terminated at 1.20 m
Full File Name: P:\WP\ADMIN\GEOTECH\TENDERS, PROPOSALS AND PROJECTS\PROJECTS\247473 COOROIBAH WATERWAY CROSSING GI\NEW FOLDER\247473 COOROIBAH_MG.GPJ
(Refusal)
1.5 8.5 1.5
2.0 8.0 2.0
2.5 7.5 2.5
3.0 7.0 3.0
3.5 6.5 3.5
4.0 6.0 4.0
4.5 5.5 4.5
Remarks: Logged: MG
- End of hole at 1.20m bgl due to hand auger refusal on gravels
- No groundwater was encountered Logged Date: 30/01/2020
- Coordinates recorded using a hand-held GPS unit (+/- 5m accuracy). Checked: JB
Elevation data was retrieved from the State of Queensland's Department of Natural Resources, Checked Date: 14/02/2020
Mines and Energy online mapping tool "Queensland Globe".
Page 11
25 King St
Bowen Hills QLD 4006
ph: +61 7 3173 8000
e: [email protected]
SOIL BH2
Client: NBN Driller: N/A Commenced:30/01/2020
Project: Cooroibah Waterway Crossing Rig: Hand Auger Completed: 30/01/2020
Location: Cooroibah Easting: 499992 m
Project Number: 247473 Northing: 7085458 m
Elevation: 10 mAHD Sheet:1 of 1
Drilling Soil Description Testing Strata
Information Information
Elevation (mAHD)
Moisture Content
MATERIAL DESCRIPTION Comments /
Consistency / DCP Values
Sample Type
Groundwater
Graphic Log
Soil Type, Colour, Plasticity or Particle Test Results /
Depth (m)
Relative Density (Blows/100mm Penetration)
Depth (m)
Characteristic, Secondary and Minor Components Origin
Method
VS S F St VSt H
VL L MD D VD C
2 6 10 14 18
USC
1 2 3 4 5 2 4 6 8 1 0 1 2 1 4 1 6 1 8
0 m: TOPSOIL:Sandy CLAY CL ~PL TOPSOIL
D Dark brown grey, low plasticity, fine grained sand with
organics (rootlets), ~PL, very stiff
D 0.4 m: Silty Sandy CLAY CI >PL ALLUVIAL
0.5 Grey mottled orange, medium plasticity, with fine to 9.5 0.5
D medium grained sand, >PL, stiff
0.6 m: becomes soft to firm
D 0.7 m: Silty CLAY CI-CH
Pale grey, medium to high plasticity, with fine grained
sand, >PL, soft to firm
0.9 m: Sandy CLAY CH
1.0 9.0 1.0
Pale grey mottled orange, medium to high plasticity, fine
grained sand, with minor fine subrounded gravel, ~PL,
D very stiff
Full File Name: P:\WP\ADMIN\GEOTECH\TENDERS, PROPOSALS AND PROJECTS\PROJECTS\247473 COOROIBAH WATERWAY CROSSING GI\NEW FOLDER\247473 COOROIBAH_MG.GPJ
1.4 m: Silty CLAY CH
HA
1.5 Pale grey, high plasticity, minor fine grained sand, >PL, 8.5 1.5
D hard
D 1.9 m: increase in moisture content
2.0 8.0 2.0
D 2.4 m: increase in sand content, medium plasticity CI
2.5 7.5 2.5
D 2.75 m: Sandy CLAY CH
Pale grey mottled yellow brown, low plasticity, fine to
D medium grained sand, >PL, hard SC W
3.0 7.0 3.0
2.9 m: Clayey SAND
Pale grey, low plasticity fines, fine to coarse grained
sand, wet
BH2 Terminated at 3.00 m
(Target depth)
3.5 6.5 3.5
4.0 6.0 4.0
4.5 5.5 4.5
Remarks: Logged: MG
- Groundwater was encountered at 1.9m bgl
- Coordinates recorded using a hand-held GPS unit (+/- 5m accuracy). Logged Date: 30/01/2020
Elevation data was retrieved from the State of Queensland's Department of Natural Resources, Checked: JB
Mines and Energy online mapping tool "Queensland Globe". Checked Date: 14/02/2020
Page 12
25 King St
Bowen Hills QLD 4006
ph: +61 7 3173 8000
e: [email protected]
SOIL BH3
Client: NBN Driller: N/A Commenced:30/01/2020
Project: Cooroibah Waterway Crossing Rig: Hand Auger Completed: 30/01/2020
Location: Cooroibah Easting: 499963 m
Project Number: 247473 Northing: 7085452 m
Elevation: 10 mAHD Sheet:1 of 1
Drilling Soil Description Testing Strata
Information Information
Elevation (mAHD)
Moisture Content
MATERIAL DESCRIPTION Comments /
Consistency / DCP Values
Sample Type
Groundwater
Graphic Log
Soil Type, Colour, Plasticity or Particle Test Results /
Depth (m)
Relative Density (Blows/100mm Penetration)
Depth (m)
Characteristic, Secondary and Minor Components Origin
Method
VS S F St VSt H
VL L MD D VD C
2 6 10 14 18
USC
1 2 3 4 5 2 4 6 8 1 0 1 2 1 4 1 6 1 8
0 m: TOPSOIL: Silty CLAY CI <PL TOPSOIL
D Dark brown, medium plasticity, with minor fine grained
sand, organics (rootlets), <PL, very stiff
D 0.25 m: decrease in sand content, high plasticity CH
D 0.4 m: Silty Sandy CLAY CI >PL ALLUVIAL
0.5 Brown grey, medium plasticity, with fine grained sand, 9.5 0.5
>PL, stiff
HA
0.7 m: becomes pale brown grey mottled red-orange
D 0.8 m: Silty CLAY CH >PL
D Pale brown-grey mottled red-orange, high plasticity, with
1.0 minor fine grained sand, >PL, very stiff 9.0 1.0
1 m: becomes stiff
D 1.2 m: becomes grey mottled yellow-brown
D
Full File Name: P:\WP\ADMIN\GEOTECH\TENDERS, PROPOSALS AND PROJECTS\PROJECTS\247473 COOROIBAH WATERWAY CROSSING GI\NEW FOLDER\247473 COOROIBAH_MG.GPJ
1.35 m: increase in fine grained sand content
1.5
BH3 Terminated at 1.37 m 8.5 1.5
(Obstruction in the hole)
2.0 8.0 2.0
2.5 7.5 2.5
3.0 7.0 3.0
3.5 6.5 3.5
4.0 6.0 4.0
4.5 5.5 4.5
Remarks: Logged: MG
- End of hole at 1.37m bgl due to hand auger refusing on protruding rock in the auger hole
- No groundwater was encountered Logged Date: 30/01/2020
- Coordinates recorded using a hand-held GPS unit (+/- 5m accuracy). Checked: JB
Elevation data was retrieved from the State of Queensland's Department of Natural Resources, Checked Date: 14/02/2020
Mines and Energy online mapping tool "Queensland Globe".
Page 13
1. Explanatory notes and abbreviations
The following information provides the terms and abbreviations used in Aurecon geotechnical
borelogs and reports. Description of soil and rock are generally in accordance with the Unified Soil
Classification System and Australian Standard AS1726-2017, Geotechnical Site Investigations. Soil
and rock descriptions using established field techniques have been recorded independent of any
laboratory test results. As far as is practicable the data contained on the log sheets is factual. Some
interpretation is inevitable in the assessment of conditions between samples and of the origin of the
materials.
Assessment of potential site contamination does not form part of this geotechnical report. Any
reference to potential contaminants is for information only, and does not necessarily indicate the
presence or absence of soil or groundwater contamination.
1.1 Soil Description
Soils are generally described in the borehole log using the following sequence of terms:
[Drilling Information]; [USC Symbol]; [Soil Type, Colour, Plasticity/Particle Description, Structure];
[Moisture Condition]; [Consistency]
Unified Soil Classification Group Symbols
Typical Names USC Symbol Typical Names USC
Symbol
Well graded gravels GW Well graded sands SW
Poorly graded gravels GP Poorly graded sands SP
Silty gravels GM Silty sands SM
Clayey gravels GC Clayey sands SC
Inorganic silts of low plasticity. ML Inorganic clay of low plasticity CL
Inorganic silts of high plasticity MH Inorganic clay of medium plasticity CI
Organic silts of low plasticity OL Inorganic clays of high plasticity CH
Organic clays of high plasticity OH Peat and other highly organic soils Pt
Soil Type and Particle Size
Major Divisions Symbols Subdivision Particle Size
Coarse Grained Soils Boulders > 200 mm
(more than 65% of Cobbles 63 mm – 200 mm
material Gravels G Coarse 19 mm – 63 mm
is larger than 0.075mm) (more than half of coarse Medium 6.7 mm – 19 mm
fraction is larger than
Fine 2.36 mm – 6.7 mm
2.36mm)
Sands S Coarse 0.6 mm – 2.36 mm
(more than half of coarse Medium 0.21 mm – 0.6 mm
fraction is smaller than
Fine 75 µm – 0.21 mm
2.36mm)
Fine Grained Soils Silts M < 75 µm
(more than 35% of Clays C
material is smaller than Organic O
0.075mm)
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Soil Plasticity
Term Symbol Range of Range of
liquid limit liquid limit of
for silt clay
Low Plasticity L ≤50 ≤35
Medium Plasticity I Not applicable ≤35 and ≤50
High Plasticity H >50 >50
Moisture Content Classification
Material Term Symbol Field Assessment
Dry D Non-cohesive and free-running
Moist M Soil feels cool, darkened in colour. Soil tends to stick
grained
together
Coarse
Wet W Soil feels cool, darkened in colour. Soil tends to stick
together, free water forms when handling.
Moist, dry of plastic limit < PL Hard and friable or powdery
Moist, near plastic limit ≈ PL Soils can be moulded at a moisture content approximately
equal to the plastic limit
Fine Grained
Moist, wet of plastic limit > PL Soils usually weakened and free water forms on hands when
handling
Wet, near liquid limit ≈ LL Near liquid limit
Wet, wet of liquid limit > LL Wet of liquid limit
Consistency Terms for Cohesive Soil
Term Symbol Field Assessment Undrained SPT DCP (Blows /
Shear N – Value 100mm)
Strength
(kPa)
Exudes between fingers when
Very Soft VS ≤12 <2 ≤1
squeezed in hand.
Can be moulded by light finger
Soft S >12 and ≤25 2 to 5 1 to 2
pressure.
Can be moulded by strong
Firm F >25 and ≤50 5 to 10 2 to 3
finger pressure.
Stiff St Cannot be moulded by fingers. >50 and ≤100 10 to 20 3 to 5
Can be indented by thumb
Very Stiff VSt >100 and ≤200 20 to 40 5 to 10
nail.
Can be indented with difficulty
Hard H > 200 > 40 >10
by thumb nail
Can be easily crumbled or
Friable Fr broken into small pieces by -
hand
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Density of Non-cohesive Soil
Term Symbol SPT Density DCP (Blows /
N – Index (%) 100mm)
Value
Very VL <4 < 15 0 to 1
Loose
Loose L 4 to 10 15 to 35 1 to 3
Medium MD 10 to 30 35 to 65 3 to 8
Dense
Dense D 30 to 50 65 to 85 8 to 15
Very VD > 50 > 85 >15
Dense
Note: Density only provided where in-situ testing is available.
Classification of Cemented Soils
Term Symbol Field Assessment
Weakly WC
The soil may be easily disaggregated by hand in air or water.
Cemented
Moderately MC
Effort is required to disaggregate the soil by hand in air or water.
Cemented
2. Rock Description
Rocks are generally described in the borehole log using the following sequence of terms:
[Drilling Information]; [Rock Type, Colour, Structure]; [Rock Quality Designation]; [Defects]
[Weathering]; [Strength];
Rock Weathering Classification
Term Symbol Definition
Residual Soil RS Material is weathered to such an extent that it has soil properties. Mass
structure and material texture and fabric of original rock are no longer
visible, but the soil has not been significantly transported.
Extremely Weathered XW Material is weathered to such an extent that it has soil properties. Mass
structure and material texture and fabric of original rock are still visible.
Highly Distinctly HW DW The whole of the rock material is discoloured, usually by iron staining
Weathered Weathered or bleaching to the extent that the colour of the original rock is not
recognizable. Rock strength is significantly changed by weathering.
Some primary minerals have weathered to clay minerals. Porosity may
be increased by leaching, or may be decreased due to deposition of
weathering products in pores.
Moderately MW The whole of the rock material is discoloured, usually by iron staining
Weathered or bleaching to the extent that the colour of the original rock is not
recognizable, but shows little or no change of strength from fresh rock.
Slightly Weathered SW Rock is partially discoloured with staining or bleaching along joints but
shows little or no change of strength from fresh rock.
Fresh FR Rock shows no sign of decomposition of individual minerals or colour
changes.
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Rock Strength Classification
Strength Symbol Field Assessment Uniaxial Point Load
Compressive Index4
Strength (Mpa) Is(50) (MPa)
Very Low VL Material crumbles under firm blows with sharp end 0.6 to 2 0.03 to 0.1
of pick; can be peeled with knife; too hard to cut a
triaxial sample by hand. Pieces up to 30 mm thick
can be broken by finger pressure.
Low L Easily scored with a knife; indentations 1 mm to 3 2 to 6 0.1 to0.3
mm show in the specimen with firm blows of the
pick point; has dull sound under hammer. A piece
of core 150 mm long by 50 mm diameter may be
broken by hand. Sharp edges of core may be
friable and break during handling.
Medium M Readily scored with a knife; a piece of core 150 6 to 20 0.3 to 1.0
mm long by 50 mm diameter can be broken by
hand with difficulty.
High H A piece of core 150 mm long by 50 mm diameter 20 to 60 1.0 to 3.0
cannot be broken by hand but can be broken by a
pick with a single firm blow; rock rings under
hammer.
Very High VH Hand specimen breaks with pick after more than 60 to 200 3.0 to 10
one blow; rock rings under hammer.
Extremely EH Specimen requires many blows with geological More than 200 > 10
High pick to break through intact material; rock rings
under hammer.
Notes on rock strength
1. Material with strength less than ‘Very Low’ shall be described using soil characteristics.
2. These items refer to the strength of the rock material and not to the strength of the rock mass
which may be considerably weaker due to the effect of rock defects.
3. Anisotropy of rock material samples may affect the field assessment of strength
4. The unconfined compressive strength is typically about 20 x Is (50), but the multiplier may vary
widely for different rock types.
Rock Defects
Defects are generally described using the following sequence of terms: [Defect Spacing]; [Depth
(metres from surface), Defect Type, Defect Angle (degrees from horizontal), Surface roughness, Infill,
Defect thickness (mm)]
Defect Description
Defect Type Surface Roughness Surface shape Coating or Infill
Bp – Bedding Parting Vr- Very Rough St – Stepped cn – clean
Fp – Foliation Parting Ro – Rough Cu – Curved sn – stained
Jo – Joint Sm – Smooth Un – Undulating vn – veneer
Su – Sheared Surface Po – Polished Ir – Irregular cg – coating
Sh – Sheared Zone Sl – Slickensided Pl – Planar
Se- Sheared Seam
Cs – Crushed Seam
Xs – Extremely weathered
seam
Is – Infilled Seam
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NOTES\EXPLANATORY NOTES AURECON 2018 V2 (002).DOC 26 February 2018 PAGE 4
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Water Support
▼ Measurement standing water level and date C Casing
∇ Water Noted M Mud
Water inflow W Water
▼
▼
Water / drilling fluid loss
3. Drilling method
BH Backhoe bucket (rubber tyred machine) Rotary drilling with flushing of cuttings using
EX Excavator bucket (tracked machine) RA - air circulation
HA Hand Auger RM - bentonite or polymer mud circulation
RC - water circulation
AV Auger drilling with steel “V” bit NMLC Coring using an NMLC core barrel
AT Auger drilling with Tungsten Carbide (TC) bit RR Tricone (Rock Roller) Bit
HOA Hollow Auger DB Drag (Blade) Bit
Field Sampling and Testing
Symbol Sample or Test Symbol Sample or Test
W Water Sample RW Rod Weight only causing penetration (N < I)
Hammer and rod weight only causing full
D Disturbed Sample HW
penetration (N < I)
B Bulk Disturbed Sample HB Hammer Bouncing
SPT Standard Penetration Test U (50) Undisturbed Sample (50mm diameter tube)
Example of blows per 150mm
7, 11, 12 (eg) PP Pocket Penetrometer Test (kPa)
penetration over 450mm
Penetration Resistance (blows
for 300mm of penetration
N = 23 (eg) FV Field Shear Vane (kPa)
following 150mm seating drived
ie 11 + 12 = 23
Rock Quality Designation expressed as:
Partial Penetration- example of
25/20mm (eg) recorded blows for the RQD Sum of lengths of sound core pieces > 100mm
measured penetration
Total Length of core section considered
Dynamic Cone Penetrometer measured in
N* Inferred SPT Value DCP
blows / 100mm
FILE P:\WP\ADMIN\GEOTECH\MISCELLANEOUS\ADMIN\FORMS\FORMS\EXPLANATORY
NOTES\EXPLANATORY NOTES AURECON 2018 V2 (002).DOC 26 February 2018 PAGE 5
Used in these records
RFI 10.03.2020 - Appendix C - Memorandum cooroibah waterway crossing.pdfRelated documentApplication case desk ↗
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